5 g (approx. 1 level measuring spoon) is added each week per 13 gallons of aquarium water. This increases the proportion of iodine to approx. 0.075 mg per liter and strontium to approx. 1.5 mg per liter. The recommended maximum dosage is 2 measuring spoons a week per 13 gallons.Tropic Marin Pro-Coral Mineral should be added in the filter/sump area of the aquarium at a sufficient distance from the return pump, in order to prevent any undissolved crystals from coming into contact with the coral.